1. Field of the Invention
The present invention relates to well completion for the production of fluids within a wellbore. More particularly, the present invention relates to completion tools, such as packers, liner hangers, and anchors. Even more particularly, the present invention relates to control of setting completion tools in the wellbore.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
Land formations producing oil and gas have different zones. There are zones producing different mixtures of oil and gas. There are zones producing other fluids, such as water. There are zones producing no fluids at all. A wellbore or casing or both can pass through any number and combination of these zones. Isolating the productive zones, containing the desired range of oil and gas, is a feature of well completion. The well is completed so as to begin production of hydrocarbons from the well.
One example is the open-hole completion for producing oil and gas in a wellbore. In open-hole wells, standard casing is cemented only into upper portions of the well, and not through the producing zones further along the wellbore. For a well completion, a liner is run from the bottom of the casing portion of the well and down through the various zones in the wellbore. In a typical production of oil and gas in a wellbore, production tubulars or production casings are inserted in the wellbore as the liner system. One completion tool is a liner hanger or anchor, which is set in the casing portion to fasten the liner system to the casing portion.
The liner system fills the interior of the wellbore past the casing portion and supports the walls of the wellbore. Liners minimize the annular space between the production tubulars and the wellbore wall for mechanical support and restriction of annular flow of fluids around the production tubulars of the liner. Due to irregularities in an un-cased wellbore wall, liners cannot prevent annular flow in the wellbore. For this reason, a liner system uses another completion tool, called a packer. A packer stops annular flow of fluids around the production tubulars. Packers isolate various zones within the wellbore and along the liner by forming annular seals, or barriers, between the liner and the wellbore wall. Fluid can no longer flow around the liner system across zones.
Open-hole well completions are particularly useful in slant-hole wells, wherein the wellbore can deviate and run horizontally for thousands of feet through a producing zone. Packers are annular isolators placed along the length of the horizontal production tubing to allow selective production from a particularly productive zone or isolation of a non-productive zone.
Completion tools must be set at the proper depth and along the proper length of the production tubular of the liner system. Various patents have been issued relating to setting packers and other completion tools in liner systems.
The conventional structure to lock the completion tool is the shear pin. The shear pins are torn, when the tool, such as the packer, is deployed to the proper location. Mechanical action shears the pin so that the expandable element of the packer can activate. Once the shear pin is ruptured, the slip devices can be expanded to affix to the wellbore or casing. U.S. Pat. No. 3,049,177, issued to Bonner on Aug. 14, 1962 shows the well known conventional shear pin. The packer is delivered to the desired location, and a mechanical severing of the shear pin sets the packer in place. U.S. Pat. No. 3,374,841, issued to Current on Mar. 26, 1968, discloses a packer set by severing shearing members. The number of shearing members varies, so that the amount of force needed to break the shearing members can be controlled. A tool with a higher number of shearing members requires more force to sever and set, so that this tool can be placed differently than a tool with a lower number of shearing members.
Another conventional structure to lock the completion tool is a chemical agent. When the completion tool reaches the desired location, a chemical reagent is introduced at the tool to trigger the expandable element to activate. Once the chemical reagent is exposed to the expandable element, the completion tool is affixed to the wellbore or casing. Alternatively, chemical shear pins can be dissolved in reaction to exposure to a chemical reagent introduced into the wellbore.
U.S. Pat. No. 7,387,158, issued on Jun. 17, 2008 to Murray et al., discloses a packer that has a main sealing element that swells after a delay that is long enough to get the sealing element into a proper position. A sleeve is removed from the packer so as to allow well fluids to contact the main sealing element so as to start the swelling process. The main sealing element swells until the surrounding tubular or the surrounding wellbore is sealed.
U.S. Pat. No. 7,143,832, issued on Dec. 5, 2006 to Fyer, discloses an annular packer arranged on the outside of the production tubing. The packer has a core that has an elastic polymer that swells by the addition of hydrocarbons. The core can be surrounded by an external mantel of rubber. The external mantel of rubber is permeable to hydrocarbons and may be equipped with a reinforcement. The core swells by absorption of hydrocarbons and the packer expands accordingly. The expansion of the packer seals the annular space between the production tubing and the well wall.
There are other known systems with means to protect the setting shear pins of completion tools, such as packer, liner hangers, and anchors.
U.S. Pat. No. 6,241,023, issued to Krauss et al on Jun. 5, 2001, teaches another system and method for setting a packer using dogs and shear pins. The dogs are set on the mandrel in a set position relative to the packer. At the intended packer location, the mandrel is pulled up to sever a first shear pin, which releases the dogs. The dogs engage the packer and mechanical set the packer with sufficient force according to a second shear pin. Once the severing of the second shear pin signifies that the packer has been set. The breakage of the first shear pin controls when the dogs are released for the breakage of the second shear pin.
It is an object of the present invention to provide an embodiment of a system for setting a completion tool to protect the shear pins for setting the completion tool during run-in.
It is an object of the present invention to provide an embodiment of a system for setting a completion tool to protect the shear pins for setting the completion tool from accidentally setting before reaching the desired location in the wellbore.
It is an object of the present invention to provide an embodiment of a system for setting a completion tool to prevent damage and wear on the mechanical link or shear pins for setting the completion tool.
It is another object of the present invention to provide an embodiment of a system for setting a completion tool with the mandrel locked to the completion tool until the completion tool is ready to be set.
It is still another object of the present invention to provide an embodiment of a system for setting a completion tool with the mandrel locked by dogs during run-in.
It is still another object of the present invention to provide an embodiment of a system for setting a completion tool with the mandrel releasing the dogs, when the completion tool is ready to be set.
It is yet another object of the present invention to provide an embodiment of a system for setting a completion tool with the mandrel releasing the dogs by a pressure pulse, when the completion tool is ready to be set.
It is still another object of the present invention to provide an embodiment of a system for setting a completion tool with the mandrel locked by dogs during run-in to withstand greater force than the mechanical link or shear pins for setting the completion tool.
It is yet another object of the present invention to provide an embodiment of a system for setting a completion tool with the mandrel engaging the completion tool with a connection stronger than a connection between the mechanical link or shear pins for setting the completion tool.
It is yet another object of the present invention to provide an embodiment of a system for setting a completion tool with the mandrel engaging the completion tool by a dog resistant to severing.
It is yet another object of the present invention to provide an embodiment of a system for setting a completion tool with the mandrel mechanically engaging the completion tool, until the completion tool is ready to be set.
These and other objectives and advantages of the present invention will become apparent from a reading of the attached specification.